Rabies threat is low, but caution advised

The number of animals testing positive for rabies spiked in the early 1990s in Massachusetts, but it has remained significantly lower for more than a decade.

Robert Sears

After spiking in the early 1990s, the percentage of animals testing positive for rabies in Massachusetts has stayed significantly lower for more than a decade.

Still, people should be wary, especially as warm-weather outdoor activities increase, state public health veterinarian Catherine Brown of Pembroke said.

Three animals, including two domestic cats in West Roxbury, have tested positive for rabies in the last few weeks.

Most of the animals that test positive for the virus are skunks and raccoons, which are more visible at this time of year because it is their mating season, Brown said.

Chances of encountering a rabid animal in the wild are very low, but it’s always wise to “enjoy wildlife from a distance,” she said.

A more likely cause of rabies exposure is a bat getting into a house, Brown said.

Twelve percent of the 756 bats that the state laboratory tested in 2006 were found to be rabid.

“There are circumstances, even if there wasn’t a bite, that cause us concern when bats are in a home,” Brown said.

If someone was sleeping in a room before a bat was discovered there, the bat should be captured and the local health department notified so the animal can be tested for rabies, she said.

Rabies can be transmitted not only by a bite but by a scratch or an animal’s saliva.

How many people are bitten by rabid animals in Massachusetts is not known because the state does not keep records, Brown said.

All animals that are tested for rabies at the state lab had contact with humans or domestic animals, she said.

Cats, dogs, foxes, coyotes, otters and woodchucks are among the animals tested most often for rabies.

Five percent of the animals tested in 1992 were found to be rabid. The figure jumped to 18 percent in 1993, when a strain of rabies that primarily infected raccoons spread from the mid-Atlantic states, Brown said.

“As with any infectious disease, you’ll initially see a large number of cases and then a drop-off,” she said.

The rabid-animal percentage has not changed significantly in the last several years.

Thirty of the 131 skunks submitted to the state lab in the first nine months of 2007 tested positive.

Braintree Animal Control Officer David Littlewood said it is not unusual for him to get five calls a day from people concerned about rabies because they have seen a skunk that looked sick.

Littlewood said people are doing the right thing when they call him, and that he often can tell whether a skunk has rabies just by seeing it.

“People are concerned that the animal is staggering, but skunks naturally wobble when they walk, and they’re not the fastest-moving creatures,” he said.

He also looks for signs that the skunk may have been injured.

Infected animals often behave strangely. They may attack people or other animals without provocation or lose their fear of people and seem unnaturally friendly.

In general, people should avoid all wild animals and not touch stray cats and dogs, Brown said.